Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2004
Publication Date: 6/1/2004
Citation: Grusak, M.A., Burgett, C.L., Knewtson, S.J., Lopez-Millan, A., Ellis, D.R., Li, C., Musetti, V.M., Blair, M.W. 2004. Novel approaches to improve legume seed mineral nutrition. Proceedings of the 5th AEP-2nd ICLGG Conference, pp 37-38. Interpretive Summary: Not required.
Technical Abstract: Grain legumes contain an array of mineral elements that are essential for animal nutrition; however, mineral concentrations are not always optimal in all legume species, or in all cultivars of a given legume. We have been interested in generating tools that will facilitate the enhancement of mineral concentrations in legume seeds, with an emphasis on the micronutrient metals iron and zinc. However, to generate these tools, we have had to address processes ranging from the molecular to the whole-plant level. Mineral deposition in legume seeds requires the integrated functioning of several processes starting at the root-soil interface and terminating at the developing embryo. Minerals are absorbed by roots via membrane-localized transporters, they are partitioned to the xylem for delivery to transpiring organs of the shoot, they may be transiently stored in vegetative source regions (i.e., leaves, pod walls), and then are phloem-loaded for delivery to developing seeds. For legume seeds, phloem transport is the predominant mechanism for mineral import, because the high humidity within pods precludes transpiration from, and xylem transport to, growing seeds. Additionally, for phloem-loading of minerals to occur, they must be present in source tissues in an adequate amount and an available form; thus, mineral partitioning to specific vegetative tissues will impact their final seed mineral concentration. To better understand these processes, we have conducted studies both with agronomic and model legumes. In this paper, we describe several approaches that capitalize on germplasm diversity, unique genetic systems, and genomic resources to identify new tools to improve legume seed mineral nutrition.